This invention pertains to a new cancellation and marking ink composition which substantially completely eliminates bleeding, smudging and eradication after its application to paper products such as stamps, envelopes and post cards.
Inks used currently in the cancellation and marking of stamps are fairly easily eradicated, thus, allowing reuse of stamps after proper cancellation and marking. Such inks suffer from sludging, setting and poor wetting in their routine use which also results in easier eradication and reuse.
The currently used carbon based inks can be easily removed from many stamps simply by washing the stamps with soap and water. This is particularly true immediately after start-up when the currently used inks tend to dry and harden on the feed rollers overnight, resulting in up to 5,000 very poor cancellations before the system begins to work properly.
The ink and the inking felt maintenance costs run approximately two million dollars per year; but in solving the maintenance problems, several complicating factors rule out the use of routine commercial inks. For example, the cancelling ink must give a clear postmark on all types of paper including plastic coated papers. Further, it must make a permanent cancelling mark on stamps which have been coated with three different types of varnish. Still further, it must not dry in the inking rollers when the machines are idle for periods up to forty-eight hours but it must dry instantly on the envelope to avoid damages.
This invention encompasses the use of 2-Ethyl-1,3-Hexanediol, Polyethylene Glycol and Diethylene Glycol to dissolve monoazochrome complex organic dyes in formulating the new ink composition solution. Upon being dispersed onto a printing surface, this ink composition dissolves the paper surface grains and diffuses into restricted fiber pores, giving a dark and permanent cancellation mark. Thus, it allows substantially complete elimination of eradication of cancellation markings by use of common solvents, such as, water, alcohols, bleach, etc.
The new ink composition ingredients can be obtained commercially or prepared by any of the commonly known methods.
One method of preparation of the new ink composition is as follows and all functional components are shown in percent by weight in the various examples:
______________________________________ Percent by Functional Weight Component A B C Ranges ______________________________________ 2-Ethyl-1, 3-Hexanediol 40.0 40.0 40.0 20.0-60.0 Carbowax PEG-400 27.0 27.0 27.0 20.0-40.0 Orasol Black CN 14.3 14.3 17.0 8.0-20.0 Quadrol 10.0 10.0 7.5 0.0-15.0 Diethylene Glycol 5.0 5.0 4.7 0.0-10.0 Tyzor TE 0.5 0.5 0.57 0.25-1.5 Triton X-45 1.6 1.6 1.6 1.0-6.0 Triton X-100 1.6 1.6 1.6 1.0-6.0 Calcofluor White RWP 0.0 0.05 0.05 0.01-0.05 ______________________________________
The Orasol Black CN is mixed, blended and dissolved in Carbowax PEG-400 and 2-Ethyl-1,3-Hexanediol. Quadrol and Diethylene Glycol are then added to this solution for control of viscosity, if needed. Wettability adjustment agents, Triton X-45 and Triton X-100 are added and the mixture is further blended. These agents also allow for a smoother and an easier mixing composition. Quadrol and Diethylene Glycol are added to adjust viscosity for specific application. A curing agent, Tyzor TE, and Calcofluor White RWP, a crime identification agent, are added to the solution as the last mixing step. The materials are mixed thoroughly at a temperature of between about 0.degree. F. to 135.degree. F. The new ink composition is a true solution and used as such.
The various components are defined as follows:
(a)-Quadrol is a N,N,N',N'-tetrakis (2-hydroxypropyl)-ethylene diamine. This material is used as a viscosity adjustment agent and a corrosion inhibitor. Another agent that can be used as a viscosity adjustment agent is Dowanol EPH (mixed phenyl ethers of ethylene glycol and diethylene glycol. Often diethylene glycol is used in conjunction with Quadrol to adjust the viscosity to match machine speed use requirement/s.
(b)-Triton X-45 and Triton X-100 are octyl-phenoxy polyethoxy ethanols, each having 5 and 9-10 ethylene oxide units respectively and are used as surfactants or wettability adjustment agents.
(c)-Tyzor TE is triethanolamine chelate of orthotitanic acid and is used as a crosslinking mechanism to cure the ink composition.
(d) Calcofluor White RWP is also known as C.I. Fluorescent Brightening Agent 61. Calcofluor White RWP, a trademark of American Cyanamid Corporation, and Uvitex OB and Tinopal PCR, trademarks of Ciba-Geigy Corporation, are used either singly or in combination to show positive tracer identification of the Postal Service ink applied (the latter two components are equivalents of Calcofluor White RWP). Uvitex OB and Tinopal PCR are not otherwise identified by the manufacturer.
(e)-Carbowax PEG-400 is a specific Polyethylene glycol having a specified number of methylene groups in its chain and is of approximate molecular weight between 380 and 420.
(f)-Orasol Black CN also known as C.I. Solvent Black 28, is a metalliferous azo-dyestuff as taught and claimed in British Specification No. 924,520, complete Specification published April 24, 1963.
The following pictorial examples illustrate the new ink composition and its ability to substantially eliminate eradication;